Acetolactate synthase, small subunit [Amino acid transport and metabolism]; Acetolactate synthase, small subunit is part of the Pathway/BioSystem: Isoleucine, leucine, valine biosynthesis

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 507042342   2 KRIVTATVRNQSGVLNRITGVMTRRHFNIESISVGHTESSDISRMTFVVHvENEQQVEQLIKQLHKQIDVLKVSDITEEA 81
Cdd:COG0440    1 RHTISVLVENEPGVLARVAGLFSRRGYNIESLTVGPTEDPGISRMTIVVE-GDERVIEQITKQLNKLIDVIKVVDLTDEE 79

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 507042342  82 MIARELALIKVATTSVSRAELYSLIEPFRAAVIDVGKDSIVVQVTGTQEKVEALIELMRPYGLKEIARTGVTAFTRSMKK 161
Cdd:COG0440   80 SVERELALIKVKADGETRSEILRIAEIFRARIVDVTPDSLTIELTGDEEKIDAFIELLKPYGILEVVRTGRVALSRGSKS 159

Small subunit of acetolactate synthase; ALS_ss_C is the C-terminal half of a family of proteins which are the small subunits of acetolactate synthase. Acetolactate synthase is a tetrameric enzyme, containing probably two large and two small subunits, which catalyzes the first step in branched-chain amino acid biosynthesis. This reaction is sensitive to certain herbicides.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 507042342   85 RELALIKVATTSVSRAELYSLIEPFRAAVIDVGKDSIVVQVTGTQEKVEALIELMRPYGLKEIARTGVTAFTR 157
Cdd:pfam10369   1 RELALIKVKADPEDRAEILRIADIFRAKIVDVSPDSLTIELTGTPEKIDAFIELLKPFGILEVVRTGRVALER 73

Acetolactate synthase, small subunit [Amino acid transport and metabolism]; Acetolactate synthase, small subunit is part of the Pathway/BioSystem: Isoleucine, leucine, valine biosynthesis

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 507042342   2 KRIVTATVRNQSGVLNRITGVMTRRHFNIESISVGHTESSDISRMTFVVHvENEQQVEQLIKQLHKQIDVLKVSDITEEA 81
Cdd:COG0440    1 RHTISVLVENEPGVLARVAGLFSRRGYNIESLTVGPTEDPGISRMTIVVE-GDERVIEQITKQLNKLIDVIKVVDLTDEE 79

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 507042342  82 MIARELALIKVATTSVSRAELYSLIEPFRAAVIDVGKDSIVVQVTGTQEKVEALIELMRPYGLKEIARTGVTAFTRSMKK 161
Cdd:COG0440   80 SVERELALIKVKADGETRSEILRIAEIFRARIVDVTPDSLTIELTGDEEKIDAFIELLKPYGILEVVRTGRVALSRGSKS 159

acetohydroxyacid synthase small subunit

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 507042342   1 MKRIVTATVRNQSGVLNRITGVMTRRHFNIESISVGHTESSDISRMTFVVHVENeQQVEQLIKQLHKQIDVLKVSDITEE 80
Cdd:CHL00100   1 MKHTLSVLVEDESGVLTRIAGLFARRGFNIESLAVGPAEQKGISRITMVVPGDD-RTIEQLTKQLYKLVNILKVQDITNI 79

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 507042342  81 AMIARELALIKVATTSVSRAELYSLIEPFRAAVIDVGKDSIVVQVTGTQEKVEALIELMRPYGLKEIARTGVTAFTRSMK 160
Cdd:CHL00100  80 PCVERELMLIKINVNSQTRPEILEIAQIFRAKVVDLSEESLILEVTGDPGKIVAIEQLLEKFGIIEIARTGKIALIRESK 159

N-terminal ACT domain of the Escherichia coli IlvH-like regulatory subunit of acetohydroxyacid synthase (AHAS); ACT_AHAS: N-terminal ACT domain of the Escherichia coli IlvH-like regulatory subunit of acetohydroxyacid synthase (AHAS). AHAS catalyses the first common step in the biosynthesis of the three branched-chain amino acids. The first step involves the condensation of either pyruvate or 2-ketobutyrate with the two-carbon hydroxyethyl fragment derived from another pyruvate molecule, covalently bound to the coenzyme thiamine diphosphate. Bacterial AHASs generally consist of regulatory and catalytic subunits. The effector (valine) binding sites are proposed to be located in two symmetrically related positions in the interface between a pair of N-terminal ACT domains with the C-terminal domain of IlvH contacting the catalytic dimer. Plants Arabidopsis and Oryza have tandem IlvH subunits; both the first and second ACT domain sequences are present in this CD. Members of this CD belong to the superfamily of ACT regulatory domains.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 507042342   3 RIVTATVRNQSGVLNRITGVMTRRHFNIESISVGHTESSDISRMTFVVHvENEQQVEQLIKQLHKQIDVLKVS 75
Cdd:cd04878    1 HTLSVLVENEPGVLNRISGLFARRGFNIESLTVGPTEDPGISRITIVVE-GDDDVIEQIVKQLNKLVDVLKVS 72

ACT domain-containing protein;

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 507042342   1 MKRIVTATVRNQSGVLNRITGVMTRRHFNIESISVGHTESSDISRMTFVVHVENEQQVEQLIKQLHKQIDVLKV 74
Cdd:PRK13562   1 MTRILKLQVADQVSTLNRITSAFVRLQYNIDTLHVTHSEQPGISNMEIQVDIQDDTSLHILIKKLKQQINVLTV 74

ACT domain; This family of domains generally have a regulatory role. ACT domains are linked to a wide range of metabolic enzymes that are regulated by amino acid concentration. Pairs of ACT domains bind specifically to a particular amino acid leading to regulation of the linked enzyme. The ACT domain is found in: D-3-phosphoglycerate dehydrogenase EC:1.1.1.95, which is inhibited by serine. Aspartokinase EC:2.7.2.4, which is regulated by lysine. Acetolactate synthase small regulatory subunit, which is inhibited by valine. Phenylalanine-4-hydroxylase EC:1.14.16.1, which is regulated by phenylalanine. Prephenate dehydrogenase EC:4.2.1.51. formyltetrahydrofolate deformylase EC:3.5.1.10, which is activated by methionine and inhibited by glycine. GTP pyrophosphokinase EC:2.7.6.5

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 507042342    4 IVTATVRNQSGVLNRITGVMTRRHFNIESISVGhtESSDISRMTFVVHVENEQQVEQLIKQLHKQID 70
Cdd:pfam01842   2 VLEVLVPDRPGLLARVLGALADRGINITSIEQG--TSEDKGGIVFVVIVVDEEDLEEVLEALKKLEG 66

ACT domains are commonly involved in specifically binding an amino acid or other small ligand leading to regulation of the enzyme; Members of this CD belong to the superfamily of ACT regulatory domains. Pairs of ACT domains are commonly involved in specifically binding an amino acid or other small ligand leading to regulation of the enzyme. The ACT domain has been detected in a number of diverse proteins; some of these proteins are involved in amino acid and purine biosynthesis, phenylalanine hydroxylation, regulation of bacterial metabolism and transcription, and many remain to be characterized. ACT domain-containing enzymes involved in amino acid and purine synthesis are in many cases allosteric enzymes with complex regulation enforced by the binding of ligands. The ACT domain is commonly involved in the binding of a small regulatory molecule, such as the amino acids L-Ser and L-Phe in the case of D-3-phosphoglycerate dehydrogenase and the bifunctional chorismate mutase-prephenate dehydratase enzyme (P-protein), respectively. Aspartokinases typically consist of two C-terminal ACT domains in a tandem repeat, but the second ACT domain is inserted within the first, resulting in, what is normally the terminal beta strand of ACT2, formed from a region N-terminal of ACT1. ACT domain repeats have been shown to have nonequivalent ligand-binding sites with complex regulatory patterns such as those seen in the bifunctional enzyme, aspartokinase-homoserine dehydrogenase (ThrA). In other enzymes, such as phenylalanine hydroxylases, the ACT domain appears to function as a flexible small module providing allosteric regulation via transmission of conformational changes, these conformational changes are not necessarily initiated by regulatory ligand binding at the ACT domain itself. ACT domains are present either singularly, N- or C-terminal, or in pairs present C-terminal or between two catalytic domains. Unique to cyanobacteria are four ACT domains C-terminal to an aspartokinase domain. A few proteins are composed almost entirely of ACT domain repeats as seen in the four ACT domain protein, the ACR protein, found in higher plants; and the two ACT domain protein, the glycine cleavage system transcriptional repressor (GcvR) protein, found in some bacteria. Also seen are single ACT domain proteins similar to the Streptococcus pneumoniae ACT domain protein (uncharacterized pdb structure 1ZPV) found in both bacteria and archaea. Purportedly, the ACT domain is an evolutionarily mobile ligand binding regulatory module that has been fused to different enzymes at various times.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 507042342   5 VTATVRNQSGVLNRITGVMTRRHFNIESISVGHTESSDISRMTFVvhVENEQQVEQLIKQLH 66
Cdd:cd02116    1 LTVSGPDRPGLLAKVLSVLAEAGINITSIEQRTSGDGGEADIFIV--VDGDGDLEKLLEALE 60

ACT domain found C-terminal of the RelA/SpoT domains; ACT_RelA-SpoT: the ACT domain found C-terminal of the RelA/SpoT domains. Enzymes of the Rel/Spo family enable bacteria to survive prolonged periods of nutrient limitation by controlling guanosine-3'-diphosphate-5'-(tri)diphosphate ((p)ppGpp) production and subsequent rRNA repression (stringent response). Both the synthesis of (p)ppGpp from ATP and GDP(GTP), and its hydrolysis to GDP(GTP) and pyrophosphate, are catalyzed by Rel/Spo proteins. In Escherichia coli and its close relatives, the metabolism of (p)ppGpp is governed by two homologous proteins, RelA and SpoT. The RelA protein catalyzes (p)ppGpp synthesis in a reaction requiring its binding to ribosomes bearing codon-specified uncharged tRNA. The major role of the SpoT protein is the breakdown of (p)ppGpp by a manganese-dependent (p)ppGpp pyrophosphohydrolase activity. Although the stringent response appears to be tightly regulated by these two enzymes in E. coli, a bifunctional Rel/Spo protein has been discovered in most gram-positive organisms studied so far. These bifunctional Rel/Spo homologs (rsh) appear to modulate (p)ppGpp levels through two distinct active sites that are controlled by a reciprocal regulatory mechanism ensuring inverse coupling of opposing activities. In studies with the Streptococcus equisimilis Rel/Spo homolog, the C-terminal domain appears to be involved in this reciprocal regulation of the two opposing catalytic activities present in the N-terminal domain, ensuring that both synthesis and degradation activities are not coinduced. Members of this CD belong to the superfamily of ACT regulatory domains.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 507042342   8 TVRNQSGVLNRITGVMTRRHFNIESISVgHTESSDISRMTFVVHVENEQQVEQLIKQLHKQIDVLKV 74
Cdd:cd04876    4 EAIDRPGLLADITTVIAEEKINILSVNT-RTDDDGLATIRLTLEVRDLEHLARIMRKLRQIPGVIDV 69

ACT domain; ACT domains bind to amino acids and regulate associated enzyme domains. These ACT domains are found at the C-terminus of the RelA protein.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 507042342    5 VTATVRNQSGVLNRITGVMTRRHFNIESISVGHTESSDISRMTFVVHVENEQQVEQLIKQLHKQIDVLKVS 75
Cdd:pfam13291   8 LEVEAIDRPGLLADITQVISEEKANIVSVNAKTRKKDGTAEIKITLEVKDVEHLERLMAKLRRIPGVIDVE 78

Glycine cleavage system regulator GcvR [Amino acid transport and metabolism];

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 507042342   5 VTATVRNQSGVLNRITGVMTRRHFNIESISVgHTESSDIS-----RMTFVVHVENEQQVEQLIKQLHKQIDVLKVsDITE 79
Cdd:COG2716   93 VEVVGNDRPGIVAEVTQFLAERGINIEDLST-KTYPAPMSgtplfSAQITVHVPAGLDIDALRDALEDLADELNV-DISL 170

                 ...
gi 507042342  80 EAM 82
Cdd:COG2716  171 EPI 173

ACT domains C-terminal to the catalytic domain of aspartokinase (AK; 4-L-aspartate-4-phosphotransferase); This CD includes the second of two ACT domains C-terminal to the catalytic domain of aspartokinase (AK; 4-L-aspartate-4-phosphotransferase). The exception in this group, is the inclusion of the first ACT domain of the bifunctional aspartokinase - homoserine dehydrogenase-like enzyme group (ACT_AKi-HSDH-ThrA-like_1) which includes the monofunctional, threonine-sensitive, aspartokinase found in Methanococcus jannaschii and other related archaeal species. AK catalyzes the conversion of aspartate and ATP to aspartylphosphate and ADP. AK is the first enzyme in the pathway of the biosynthesis of the aspartate family of amino acids (lysine, threonine, methionine, and isoleucine) and the bacterial cell wall component, meso-diaminopimelate. One mechanism for the regulation of this pathway is by the production of several isoenzymes of AK with different repressors and allosteric inhibitors. Pairs of ACT domains are proposed to specifically bind amino acids leading to allosteric regulation of the enzyme. In Escherichia coli (EC), three different AK isoenzymes are regulated specifically by lysine, methionine, and threonine. AK-HSDHI (ThrA) and AK-HSDHII (MetL) are bifunctional enzymes that consist of an N-terminal AK and a C-terminal homoserine dehydrogenase (HSDH). ThrA and MetL are involved in threonine and methionine biosynthesis, respectively. The third isoenzyme, AKIII (LysC), is monofunctional and is involved in lysine synthesis. The three Bacillus subtilis (BS) isoenzymes, AKI (DapG), AKII (LysC), and AKIII (YclM), are feedback inhibited by meso-diaminopimelate, lysine, and lysine plus threonine, respectively. The E. coli lysine-sensitive AK is described as a homodimer, whereas, the B. subtilis lysine-sensitive AK is described as is a heterodimeric complex of alpha- and beta- subunits that are formed from two in-frame overlapping genes. A single AK enzyme type has been described in Pseudomonas, Amycolatopsis, and Corynebacterium, and apparently, unique to cyanobacteria, are AKs with two tandem pairs of ACT domains, C-terminal to the catalytic domain. The fungal aspartate pathway is regulated at the AK step, with L-Thr being an allosteric inhibitor of the Saccharomyces cerevisiae AK (Hom3). At least two distinct AK isoenzymes can occur in higher plants, a monofunctional lysine-sensitive isoenzyme, which is involved in the overall regulation of the pathway and can be synergistically inhibited by S-adenosylmethionine. The other isoenzyme is a bifunctional, threonine-sensitive AK-HSDH protein. Also included in this CD are the ACT domains of the Methylomicrobium alcaliphilum AK; the first enzyme of the ectoine biosynthetic pathway found in this bacterium and several other halophilic/halotolerant bacteria. Members of this CD belong to the superfamily of ACT regulatory domains.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 507042342   4 IVTATVRNQSGVLNRITGVMTRRHFNIESISVGHTESSdisrMTFVVHvenEQQVEQLIKQLHK 67
Cdd:cd04892    5 VVGAGMRGTPGVAARIFSALAEAGINIIMISQGSSEVN----ISFVVD---EDDADKAVKALHE 61

homoserine dehydrogenase; Provisional

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 507042342   1 MKRIVTA-----TVRNQSGVLNRITGVMTRRHFNIESIsVGHTESSDISRMTFVVHVENEQQVEQLIKQLHKQIDVLKV 74
Cdd:PRK06349 342 MEEIESKyylrlLVADKPGVLAKIAAIFAENGISIESI-LQKGAGGEGAEIVIVTHETSEAALRAALAAIEALDVVLGI 419